20,651 research outputs found

    Operational Integrator-Patent

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    Solid state operational integrato

    Operational integrator

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    System operates in the nonreturn-to-zero mode, maintaining the increased bit density capability of this mode but with much higher noise immunity than conventional schemes offer. This integrator performs a mathematical integrating function on inputs from 100 Hz through 100 MHz

    From meson-nucleon scattering to vector mesons in nuclear matter

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    We employ meson-nucleon scattering data to deduce the properties of the low-mass vector mesons in nuclear matter, and present results for the ρ\rho and ω\omega in-medium spectral functions. The corresponding thermal emission rate for lepton pairs is also discussed.Comment: Talk given at 28th International Workshop on Gross Properties of Nuclei and Nuclear Excitations, Hirschegg, Austria, 16-22 Jan. 200

    Satisfiability of CTL* with constraints

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    We show that satisfiability for CTL* with equality-, order-, and modulo-constraints over Z is decidable. Previously, decidability was only known for certain fragments of CTL*, e.g., the existential and positive fragments and EF.Comment: To appear at Concur 201

    Do We Really Know that Oil Caused the Great Stagflation? A Monetary Alternative

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    This paper argues that major oil price increases were not nearly as essential a part of the causal mechanism that generated the stagflation of the 1970s as is often thought. There is neither a theoretical presumption that oil supply shocks are stagflationary nor robust empirical evidence for this view. In contrast, we show that monetary expansions and contractions can generate stagflation of realistic magnitude even in the absence of supply shocks. Furthermore, monetary fluctuations help to explain the historical movements of the prices of oil and other commodities, including the surge in the prices of industrial commodities that preceded the 1973/74 oil price increase. Thus, they can account for the striking coincidence of major oil price increases and worsening stagflation.

    TRPC1 regulates calcium-activated chloride channels in salivary gland cells

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    Calcium-activated chloride channel (CaCC) plays an important role in modulating epithelial secretion. It has been suggested that in salivary tissues, sustained fluid secretion is dependent on Ca2+ influx that activates ion channels such as CaCC to initiate Cl- efflux. However direct evidence as well as the molecular identity of the Ca2+ channel responsible for activating CaCC in salivary tissues is not yet identified. Here we provide evidence that in human salivary cells, an outward rectifying Cl- current was activated by increasing [Ca2+]i, which was inhibited by the addition of pharmacological agents niflumic acid (NFA), an antagonist of CaCC, or T16Ainh-A01, a specific TMEM16a inhibitor. Addition of thapsigargin (Tg), that induces store-depletion and activates TRPC1-mediated Ca2+ entry, potentiated the Cl- current, which was inhibited by the addition of a non-specific TRPC channel blocker SKF96365 or removal of external Ca2+. Stimulation with Tg also increased plasma membrane expression of TMEM16a protein, which was also dependent on Ca2+ entry. Importantly, in salivary cells, TRPC1 silencing, but not that of TRPC3, inhibited CaCC especially upon store depletion. Moreover, primary acinar cells isolated from submandibular gland also showed outward rectifying Cl- currents upon increasing [Ca2+]i. These Cl- currents were again potentiated with the addition of Tg, but inhibited in the presence of T16Ainh-A01. Finally, acinar cells isolated from the submandibular glands of TRPC1 knockout mice showed significant inhibition of the outward Cl- currents without decreasing TMEM16a expression. Together the data suggests that Ca2+ entry via the TRPC1 channels is essential for the activation of CaCC.Fil: Sun, Yuyang. University Of North Dakota; Estados UnidosFil: Birnbaumer, Lutz. National Institutes of Health; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Singh, Brij B.. University Of North Dakota; Estados Unido

    Scattering of vector mesons off nucleons

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    We construct a relativistic and unitary approach to 'high' energy pion- and photon-nucleon reactions taking the πN,πΔ\pi N, \pi \Delta, ρN\rho N, ωN\omega N, ηN,KΛ,KΣ\eta N, K \Lambda, K \Sigma final states into account. Our scheme dynamically generates the s- and d-wave nucleon resonances N(1535), N(1650) and N(1520) and isobar resonances Δ(1620)\Delta(1620) and Δ(1700)\Delta(1700) in terms of quasi-local interaction vertices. The description of photon-induced processes is based on a generalized vector-meson dominance assumption which directly relates the electromagnetic quasi-local 4-point interaction vertices to the corresponding vertices involving the ρ\rho and ω\omega fields. We obtain a satisfactory description of the elastic and inelastic pion- and photon-nucleon scattering data in the channels considered. The resulting s-wave ρ\rho- and ω\omega-nucleon scattering amplitudes are presented. Using these amplitudes we compute the leading density modification of the ρ\rho and ω\omega energy distributions in nuclear matter. We find a repulsive energy shift for the ω\omega meson at small nuclear density but predict considerable strength in resonance-hole like ω\omega-meson modes. Compared to previous calculations our result for the ρ\rho-meson spectral function shows a significantly smaller in-medium effect. This reflects a fairly small coupling strength of the N(1520) resonance to the ρN\rho N channel.Comment: 78 pages, 19 figures, moderately revised version, accepted in Nucl. Phys.

    Saturation from nuclear pion dynamics

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    We construct an equation-of-state for nuclear matter based on the chiral Lagrangian. The relevant scales are discussed and an effective chiral power expansion scheme, which is constructed to work around the nuclear saturation density, is presented. A realistic equation-of-state is obtained by adjusting one free parameter, when the leading and subleading terms in the expansion are included. The saturation mechanism is due to correlations induced by the one-pion-exchange interaction. Furthermore, we find a substantial deviation from the Fermi-gas estimate of the quark condensate in nuclear matter already at the saturation density.Comment: revised version, with minor corrections, 13 pages, 3 Postscript figure

    From meson- and photon-nucleon scattering to vector mesons in nuclear matter

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    We present a relativistic and unitary approach to pion- and photon-nucleon scattering taking into account the πN\pi N, ρN\rho N, ωN\omega N, ηN\eta N, πΔ\pi\Delta, KΛK \Lambda and KΣK \Sigma channels. Our scheme dynamically generates the s- and d-wave nucleon resonances N(1535), N(1650), N(1520) and N(1700) and isobar resonances Δ(1620)\Delta(1620) and Δ(1700)\Delta(1700) in terms of quasi-local two-body interaction terms. We obtain a fair description of the experimental data relevant for slow vector-meson propagation in nuclear matter. The s-wave ρ\rho - and ω\omega -meson nucleon scattering amplitudes, which define the leading density modification of the ρ\rho- and ω\omega -meson spectral functions in nuclear matter, are predicted.Comment: 6 pages, 1 figure; contribution to the Int. Workshop XXX on Gross Properties of Nuclei and Nuclear Excitations: Ultrarelativistic Heavy Ion Collisions, Hirschegg, Jan. 13-19, 200
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